Destruction of monitoring wells
Summary of water district standards

Permit and license requirements

• Permits are required for all well destructions. There are no fees for permits. All permit applications must have original signatures. Please call (408) 265-2607, ext. 2660, for permit applications or download one [PDF].
• All well destruction activities must be completed by a California C-57 licensed contractor.

Sealing requirements

• An authorized water district representative will determine the appropriate destruction method for the well based on the well construction and/or administrative issues. The typically accepted monitoring well destruction methods are: 1) The well may be drilled out to the true total depth of the original boring and the resultant boring backfilled with approved sealing material; or, 2) the well may be pressure grouted in place. During the pressure grouting procedure, a minimum of 25 pounds per square inch must be maintained for five minutes or until pumping refusal.
• In some cases, additional sealing requirements will be stipulated on the permit. Be aware that district well standards are, in some cases, more stringent than the state of California well standards.
• All waste generated during destruction activities must be properly managed: this includes, but is not limited to, all waters generated during debris removal or seal placement.

Removal of pump apparatus and debris

• All debris, silt, and pumping hardware must be removed from the well before it is backfilled.

Acceptable sealing materials

• Pressure grouting must be completed using neat cement grout. No aggregate sealing materials may be used.
• Boreholes resulting from well drill-outs, may be backfilled with neat cement grout, 10-sack sand cement grout, or hydrated high solids 20 percent bentonite slurry. No bentonite chips or pellets are allowed.
• Up to 5 percent bentonite clay may be added to a cement mixture.

Placement of sealing materials

• A tremie pipe must be used to place the cement sealing material if the well is more than 30 feet deep or if more than 3 feet of water is present in the well.